Suspicious M365 Sign-In from Synthetic iPhone User Agent via m365

ATT&CK techniques

Defense Evasion → Lateral Movement

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
- T1550.001Application Access Token
Cred Access
Discovery
Lateral Movement
- T1550.001Application Access Token
Collection
C2
Exfiltration
Impact

What it detects

This rule detects Microsoft 365 sign-ins presenting a synthetic iPhone user agent string carrying an implausible Version/26 token. Operators in the Railway PaaS token replay campaign forged iOS user agents when replaying stolen tokens, so this crafted device string is an indicator of non-genuine client access to the tenant.

Reporting behind it

Related detections9 linkedT1550.001 — drag to rearrange

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Suspicious M365 Sign-In from Synthetic iPhone User Agent via m365

Pivot detection · T1550.001 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

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